A recent targeted attack that used Chinese malware compromised over 1,000 computers belonging to dozens of South Korea organizations, according to researchers from Israeli security firm Seculert.

The main malware tool used in the attack is called PinkStats and has been used by several Chinese-language groups to target different organizations and nation states from around the world during the past four years, the Seculert researchers said Tuesday in a blog post.

PinkStats is designed to download and install additional malicious components after it infects a computer and then report successful installations to its command and control server.

In the South Korean attacks, the malware installed a common Chinese attack tool called "zxarps" that acts as a worm on the local network, the Seculert researchers said.

The "zxarps" tool uses a technique called ARP poisoning to intercept Web sessions from other computers on the network and inject a malicious ActiveX component into them. If executed, the ActiveX control installs the PinkStats malware.

The malicious component was signed with a valid digital certificate issued by certificate authority Thawte to what is likely a fake company with a South Korean name, the researchers said.

A second component installed by PinkStats is a malware tool used to launch DDoS (distributed denial-of-service) attacks. The component masquerades as software developed by South Korean antivirus vendor AhnLab.

The attackers don't seem to have sent any specific instructions to the DDoS malware yet, the Seculert researchers said. However, it is reasonable to assume that this could change at any time, they said.

Data obtained by Seculert researchers from a PinkStats administration panel suggests that over 1,000 computers in South Korea were infected in the recent attack. Many of those machines belong to universities and other educational institutions.

Even though there has been speculation that Chinese-speaking hackers have attacked South Korean organizations before, PinkStats seems to be the first proof of such an attack, the Seculert researchers said.

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